Water current responsive device for ships



p 10 1940- c. VON DEN STEINEN 2214710 WATER CURRENT RESPONSIVEDEVICE FORSHIPS Filed Ost. 1a,- 19sv 3 She ets-Sheet 2 Fiy.5.

Sept. 10. 1940; V DEN STENEN 2,214710 WATER CURRENT RESPONSIVE DEVICE FORSHIFS Filed Ost. 13, 1937 3 Sheets-Sheet 5 Patented Sept. 10, 1940 PATENT OFFICE WAI'EB CURBENT RESPONSIVE DEVICE' FOR SHIPS Carl iron den Steinen, Bergedorl', near Hamburg Germany, ass.lxnor to Askania-Werke A. G., a corporatlon o! Germany Appllcatlon October 13, 1937, Serlal Nt'l. 168,835

In Germany October 28, 1936 8 Chinas.

'I'his Inventlon relates to devices for determinlng the actlon 015 water: currents on floatlng b- Jects, such es ships er the llke, for the purpose 015 elther scientifically determining the quality und quantlty o1 water currents or forapplying such knowledge for the stabillzatlon of the float- Ing objects.

V Objects, alms und advantages of thls lnventlon will become apparent Irom the descriptlon and- Flg. 1 ls a diagrammatic illustratlon of the m0vement cf water particles and objects floatlng 20 on and in the water under the actlon o1. a wave. Flg. 2 is a sectional elevationof a ship equipped with a. water current responslVe 'device according to thls lnveritlon.

Flg. 3 ls a. slde elevation of a detall of Fix. 2, 28 partly in sectlon. 1

Flg. 4 lsa modified I0rm of a water current responslve instrument of Flg. 2..

Flg. 5 is a sectional vlew of a; shlp equlpped wlth another form of water curreht responsive 30 devlce. Flg. 6 is a diagram lllustratlng, how impulses derived irqm transverse water currents may be utlllzed for Stablllzlng shlps.

It ls a well-known l'act that the molecules or partlcles 015 which the water ls composedare 36 at rest and have no movement relatlvely to each other when the sea. 1s calm. Under the actlon of a storm or other causes, produclng waves, the water partlcles begln to move. From this conslderatlon lt becomes easily apparent that an object 40 floatlng in or on the water will be lnfluenced by the relatlvedis'placement of the water partlcles in that a certaln force ls exerted on such objects. Flg. 1 ls a vertlcal cross sectlon through a wave and shows how the water partlcles are displaced relatively t o each othex. The surtace o! the water l0risesto a top H to slopedown beyond thispolntat I2. 'I wo objects, a flatboard I3 and a buoyant pole H, loaded at the bottoni by a weight I5 are shown as floatlng on or in the 50 water. It may be assumed 1'0r the purpose 01 Illustration that the water particles were arranged in vertlcal planes when the water was calm. Under the lnfluences of periodlc waves the water partlcles are moved out of the posltion whlch they had assumed incalm water a.nd the primarlly vertlcal particles planes become lnflect- 1 ed. as lndlcated by thecurved llnes l6a I6b, l6c. etc. When lnvestlgating the line in which a supposed partlcle plane intersects the surface 01 k the water I have found that the lnflection o1 the 5 plane wlth respect to the true vertlcal is ot equal magnitude but opposltely dlrected as a plane normal to the surface of the water at the respec tive llne. 'I'h1s ls lllustrated in Flg. 1 by the llnes V lndlcating the truevertlcal, the llnes I lndicat- 10 ing the lnflectlon of the respective plane und the lines N lndlcatlng the dlrection normal to the surface of the water. 'I'he lnflection o1 the particle plane is illustrated by the lncllnatlon cf the pole I4 which is substantlally the same as the incllnation of the respectlve partlcle plane.

As the pole does not assume the lncllned positlon except under influence cf a force acting on the pole, lt follows that a water current resultlng from the relative movement o! the water partlcles acts on objects extending downwardly into the water. A relatlvely flat object, such as the board I3, ls naturally notsubstantlally affected by such currents and remalns parallel wlth the surface o1 the water.

As a shlp extends into the water exposlng thereby a substantlal part ot lts surface to water currents, lt vlfollows that a knowledge 01 the aforem ntioned water currents 1s o! great 1mportant:e Ior theproblem 012 stabillzingshlps.

It ls, ccordlngly, an object o! th1s inventlon to provl e an lnstrument by means o! whlch the action 01 water Currents directed transversely to the longitudinal axls 011 the shlp may be determined.

It ls a Iurther object 015 thlslnventlon to provlde -a devlce by means o! whlch Impulses derlved from such transverse water cur rents may' be applled in stabillzing shlps.

In Flg. 2 two devices are shown b'y means of which the magnltude 01 transverse water currents may be determlned and also impulses be derlved therefrom for the purpose o! stablllzing-shlps.

For determlnlng the magnltude o1 the Iorce exerted on a. shlp by transverse water=currents I iound lt sultable toexpose" a surface to the eurrent and to neutrallze the water Iorce tendlng to dlsplace the surface, whereby the neutrallzlng Iorce becomes a measure of the magnltude 01' the water current actlng on the shlp. For thls purpose a keel surtace 20 ls shown as movably mounted in the shlp 2l wlth lts shatt 22 which ls supported in bearlngs 23 and 24, the latter bearlng being provided wlth a stuflng box 25 Ior preventing a leakage 01 water lnto the'lnterlor of the ship. An arm 26 is secured to the end of the shaft 22 to the free end of which springs 21 and 28 are attached.

In order to obtain accurate measurements I find it advisable to use tension springs rather than compression springs, since the latter have the tendency to yield sideways, instead -of maintainlng their proper axes. The spring 21 is therefore tensioned between the arm 26 and a fixed point 29 thereby tending to turn the arm clockwisely. The second spring 28 is arrangecl between the arm and an adju stable bracket 30 having a screw threaded bore forengagement With a threaded spindle 3I. The spindle is rotatable by means of a reversible moi;or 32 mountecl on a base 33. The motor is suppled with current from a battery 34 and controlled by rneans of fixed contacts 35 and 36 between which a movable contact 31 on the arm 26 is arranged.

It is apparent that upon movement 0f the bracket in a direction towards the motor the tension of the spring 28 is increased and the arm 26 moved counter-clockwisely, while upon a movement in an opposite direction the spring 28 is releasecl causing the spring 21 120 turn the lever in the opposite direction.

The action o1 the device, so far described, is as follows:

A transverse current moving in the direction cf the arrow 38 -relatively -to the shipwill exert a force on the keel 20 turning the lever 26 in a counter-clockwise direction. The contacts 35 and 37 are closed, thereby causing the motor 32 to turn the spindle and move the bracket 30 away from the motor until the force of the spring 2'lcauses the contacts to break. It becomes thus apparent thai. the relative position of the spindle and the bracket are a measure of the magnitude of the transverse current. For indication of theymagnitude I have shown a pointer39 attached to the bracket and moving relatively to a fixed scale -4li.

When it is desirable not to increase the wetted surface of the shlp the surface exposed to the action of the water current may be arranged fiush with. the ships hull. T0 illustrate this embodiment the shipshull in Fig. 5 is shown as provided with a charnber formed byan inner wall M and a, movable surface or plate 42. The platze is provided with guide bars, one of which is shown as 43, and movable in bearings 44 and G5. To the end of the bar an arm 46 i' secured acted upon by sprlngs 47 and 48 and controlling a contact 69 movabie between fixed contacts 56 and 5l. For illustrating the tension 0f the springs a motor 52 is shown fed from a battery 53 and coxitrolled by contacts 49, 50, and 5I. The motor turns a spindle 53 for displacing a bracket 55 relatively th ereto, thereby adjustingthe ten'sion of the springs. 1

A transversewater current exerts a friction on the surface 42 which, otherwise, is not affected by a fiow of water in longitudinal direc'- tion of the shlp, as the surface is not movable in vthe longitudinal direction. Upon a displacement 02. the surface 42 relatively to the hull the contacbs 49, 50, and 5I are actuated andthe springe adjusted until the Irictlonal force 01 the water is neutralizecl.

It h.as become a practir:e .to equip ships wirth fixed bilge keels in order to reduce the rolling movement. The bilge keels extend'ing into the -wate r are supposed to act as a break and serve to dampen the rolling movement. Greatly to the surprise of naval archltects lt was found versible motor 52 bilge keelshave the tendency to roll worse than before. As far as I am aware no explanation for this unexpected behaviour was found heretofore. Many expriments conducted with the hereinbefore described apparatus for determining the magnitucle of 'transverse water currents have shown that under ceitain conditions bllge keels, instead of dampening the rolling movement increase the same by being actedupon by transverse currents. Stabilized ships and ships having a relative small inherent stability are badly afiected by transverse cu.rrents.

ACcording to this inverltion I therefore propose to derive an impulse from the magnitude of the transverse currents and to apply the same in controlling a stabilizing force acting on the ship. v

In my copending application Ser. N0. 93,024 of July 28, 1936, I have disclosed a method of, and an apparatus for, stabilizing a ship With. res'pect to the true, or to the apparent, vertical. Reference may be had to the descrii tion ofmy application for particulars.

As an example for the application 0f the present invention for stabilizing purposes there is shown in Fig. 5 a reversible -motor 56 controlled by a stabilizer 51 and equipped with a propeller 6l is shown as. associated with the stabilizer arm 46 acted upon by springs- 4'! and 48' ls provided With a contact 49' movable between fixed contacts and 5! t0 control the re- The motor;turns aspindle 54' upon which a bracket ;ls. movable, the latter being preventecl irom rotating wlth the splndle loy means of a guidingbar S2 For reading the resulting force of the springs .a pointer 63 and scale 64 are shown.

For controlling the stabilizing motor 56 in response to the magnitude of .the transverse Current controlling impulses arederlved in thls embodimentiromthe bracket 55 by means of a flat spring 65engaging a. lever 65; A positional impulse proportional to the inclination of the ship with respect to the true vertical is derived. from a gyro vertical 61 also equipped with a flat spring 68 and actingupon a i'ever 69. The levers 66 and 59 are linked to a double armed lever. 10 imparting a combined movement to a connecting lever'lf to one end of a controlling double armed lever.. 12. The coutrolling lever is connected 1:0 acton a relay for controlling the source ot' stabilizing power acting on the ship. In the illustrated embodiment the :relay is shown as being of the WeII-known Askania jet-pipe type. A jet-pipe -13 sup- I8. 'I'he plston ls corinected to apiston 'rod 18 and. 'conhect'ed to operate a m0va]ple c0ntact a.s ldllow3:

upbn ithe adt1gn 'of a tran sverse currenttb whlch jthe current responslve instrument respoxid sg or jother 01 the receptlonconduits Hand 15. [Ihe're'- ntll throu'gh the restorln'g connectlon 82,1the relay ls"restoredtojlts fneutral positlon. Whil'e normallythe 30ntrolllng contact 88 ls '}3ositipned motorls at rast, tl1e mbtor will be caused to tu'rn in the 'one or the 0t her d lrectlon upon a glisplacementfoi the movable cpntact from lts middle posltlon. The propellerf 58 will, accordingly,

cause a moment to be'exerted on the shlp counter-actlng the transverse current and other forces causlng'the ship to roll.

Sinne lt is often desirable not to increase the wetted surface cf the hull, the movable bilge keel may be made retractable as shown in Fig. 4. Abflge keel is movably mounted with its shatt 86 in a piston like suppo'rt 81, slidable in a cylinder shapecl openlng 88 in the bottom of the shlp. The support 81 may be raised or lowered by nxeans of a crank 89 and pinion 90 meshing wltha rack bar 9I. The keel is provided with the usual arm 92 having a s1ot 93 in this embodlment and engaging a. pln 84 of a bar 95, slidmeans for exertlng stabllizlng movements transversely an the shlp, a member on the shlp's hull below the water llne lncludlng a surface exposed to dlsplacement IOI'CGS of the water particles ca.used by the waves; means suppor'tlng said member Ior movement back and forth In a path transverse to the longitudinal axis of the shlp; yleldable meanS operatlvely connected to said member and blaslng lt to a neutral posltlon; power means and means operatlvely connectlng the power means to sald member to act in opposltlon to the dlsplacerpent .force; control means for the power means operatlvely connected to and actuated by movements of sald member, whereby the power means acts to malntaln sald member substantlally in lts neutral posltlon;

means operatlvely connected to the power means 2 In a stablllzlng System forshlps; 'lnclucllng means for exertlng stablliflfl movernents transversely on the' shlp, a member on the shlps hull below the waterillnej' lncludlng a surfaceexposed 't0 dlsplacement forces of the watar partlcles eaus d by the waves; means supporting sald member Ior movement back and forth in a path member to act in opppsltion 'to the 'cllsplzeement fdrce; control m eans foiflthe motor op'eratlvely connected to "and actuated by movements of sald member, wher'eby the meniberjls malntained sub- Stantlalfy in lts neutral 1aosltion; and force rneaauring'rnearis'operated by sald motor.

3. In a stabllizing system'for sl 1ips lncludlng means for exerting stabll izing mo vements transverSely n 'the Ship, a plate mounted' on thc a ships hull below the 'watjer llne and exposed t' displacernerxt forees 'c f Watei" partlizles baused by the 'waves; supporting mean sfor sa;id plate includinig ss1aenslon means and sllde bearlngs therefor triansyersely qf the' s hip gui'dlng lt to re- Ciprocriteftranlsversely of the shlp; an arm cdnhected tc) and mdvable by 'sal d suppbrting means; OPDQSECI sPrlngs c0nr'1ected to saidarm and blaslng said plate to a neutral p0sltion; a reversible motor; control means for the motor operatively connected to said arm, whereby the motor operates in response t0 slight reclprocating movements of said plate; and means operatively connectlng said motor to sald arm act on sa.id plate-in opposition to the displacement force and thereby simultaneously obtain a measure of said force.

4. In a stabilizing system for shlps includlng means for exerting stabillzing movements transversely on the ship, a. plate mounted 011 the shlps hull below the water llne substantially flush wlth the outer surface of the hull and. exposed to displacement forces of water particles caused by the waves; supporting means for said platze lncludlng suspension meansand. slide bearlngs guiding lt to recirirocate transversely of the shlp; an arm counected to and movable by said supportlng means; opposed springs connected to said arm and blasing said plate to a neutral position; areverslble motor; means connectlng the motor to be controlled by slight reciprocating movements of sald -plate; a screw-threaded spindle operated by said motor; a bracket member operable by sald spindle and. connected to one of sald sprlngs to act on said arm and platze in Opp0sltion to the displacement force; and force measuring means assoclated wlth sald bracket member.

' verse to the longitudinal axls of the ship; resillent means operatlvely connected to sald member and biaslng lt to a neutral positlon; power means operatively connected to sa1d member; control means for the power means operatlvely connected to sald member and actuated by its movements, whereby the power means acts in oppositlon to the displacement force to maintain sald member in a. neutral position; and force measurhig means also operatively connected to and actuated by said power means, whereby the dlsplacement forces may be determlned.

6. In apparatus cf the class described, a ships hull having a recess Iorme'zd therein bialow the water line, said recess havlng slde walls; a platze positloxled in sald recess sub'stantlallvflush wlth the 0utside surface ofthe hull and exposed to dlsplacement forces 01 the water'particles caused bythe waves; supporting meanS for the plate mbu nted In sald ;ec'ess behlnd the plate includin g suspensionmembers apprqltlmately parallel wlth the plate; slide bearlngs in salcl walls carrying said supportlng means, said bearlngs arranged transversely .of the' shlp to permit slight rediprolongitudinal axis o1 the ship, said measuring plate belng movably mounted oh the shlps body and actuated by sald water currents; pow'er means for exertlng a counterforce on said nieasurlng platze 1n Qpposition 150 the tran'sverse force to b'e mesJsured so as to hold the measuring platze In sbsta'ntlally the Same posltlon relative to vthe means in re'sponse.to said cpuntertorce;' and nieans f0r lndlcatlng the magnltude 01v the force fof the watercurrer'xts. 8. In a sta;billzlhg system for shlps,measuflng means responslve to the actlon cf transverse water currents'on theship resultlr'1g 1rom the relative displacement of the watdar, parti cles. caused by the waves, said measurlng mea'nsjlhcluding a su1face tor measurlng the miagnltude. o1 the transverse force exerted by sald'water Current, sald surface belngmovaibly mpunted On'the shipS body so ajs;to be actuated by sald currezj1ts transverse to the longltdlnalaxls'ot the s hih;

power means for exertlng acounterforceonsa1d surface in opposition to the transverse1or'ce tobe measured so as to hold the Surface' in substantlally 80 the same positlon relative to the sh1p; n'xeans operatlvely'qonneeted to be controlld by sald pqwer me'ans in response tasald counterforce; second means Io r exertlngp a stablllzlng moment on t;he shlp; m ea'ns responslve to the magnltude cf sald transverse tqrce t or controlllngsald second p0wer means; and means for lndlcating the magnltude of the fbrce 01 the water curr ents. CARL von nur: STEIN EN. 

